The present invention relates generally to the field of silicon wafer fabrication equipment useful in the manufacture of semiconductor devices, more particularly to apparatus for depositing an epitaxial layer from a source gas by the chemical vapor deposition (CVD) method, and especially to improvements in such apparatus when used with robotic loading of wafers.
Apparatus of the above type is used in the fabrication of semiconductor devices on 100 millimeter or larger wafers of silicon. Epitaxial layers are formed on the surfaces of the wafers by heating them to temperatures in the region of 1100 to 1200 degrees Celsius in a bell jar containing a gaseous atmosphere consisting of a hydrogen carrier gas mixed with one or more reactive gases such as a silicon source gas or a dopant source gas.
In order to provide automatic processing of a large number of wafers, a robotic loader, together with the necessary control electronics, can be used to automatically load unprocessed wafers onto the susceptor which is used to support them. The susceptor is then loaded into the reaction chamber, processing is carried out, and the susceptor is removed from the reaction chamber, whereupon the robot removes the processed wafers from the susceptor and loads unprocessed wafers.